Automatic reversing mechanism



June 4, 1935. H. E. M CRERY AUTOMATIC REVERSING MECHANISM Filed March23, 1931 INVENTOR 5 Shee ts=-Sheet l Filed March 25, 1931 5 Sheets-Sheet2 INVENTOR June 4, 1935. McCRERY 2,003,719

AUTOMATIC REVERSING MECHANISM Filed March 23, 1931 5 Sheets-Shqet 5INVENTOR MAM- M June 4, 1935. H. E. M cRERY 21,03,719

AUTOMATIC REVERSING MECHANISM Filed March 23, 1931 5 Sheets-Sheet 4 JZHJune 4, 1935. H. E. M CRERY AUTOMATIC REVERSING IECHANISI Filed March25, 19:51-

5 Sheets-Sheet 5 INVENTOR Patented June 4, 1935 UNITED STATES 2 ,003,719AUTOMATIC amasmc MECHANISM Harold E. McCrery, Pittsburgh, Pa., assignorto Blaw-Knox Company, Blawnox, Pa., a corporation of New JerseyApplication March 23, 1931, Serial No. 524,503

2 Claims.

This invention relates generally to a method of and apparatus for mixingconcrete or like material, and more particularly to a method of andapparatus for reversing the direction of ro- 6 tation of the mixingapparatus during the interval between charging and discharging so as toobtain more thorough mixing of the contents of the mixer drum.

In the accompanying drawings which illustrate the present preferredembodiment of my invention- Figure 1 is a side elevation of a truckmixer;

Figure 2 is a plan view with the rotatable drum removed, and showing thesupporting yokes for the drum, and the drum driving means;

Figure 3 is a horizontal section through one of the drum supportingyokes, the view being taken on the line IlI-III of Figure 2;

Figure 4 is a plan view of the reducing and reversing mechanism by meansof which the rotation of the mixing apparatus may be reversed eitherautomatically or manually;

Figure 5 is an enlarged plan view of the reducing mechanism shown inFigure 4, parts being shown in section;

Figure 6 is a vertical section taken on the line VI-VI of Figure 4, andillustrating the reversing mechanism; and

Figure 7 is a longitudinal section through the driving shaft andclutches forming a part of the reversing mechanism.

Referring more particularly to Figures 1, 2 and 3, the mixer comprises arotatable drum 2 which is octagonal in cross-section and is providedwith circular rings or tracks 3 through which the drum is rotated. Thedrum is provided with a charging opening 4 through which the material tobe mixed is introduced, and with a discharging opening which may beclosed by a cover 5, the operating and locking mechanism for the cover 5being indicated generally by the reference numeral 6.

The interior of the drum is provided with vanes 1 disposed at an angleto the direction in which the drum rotates so that rotation of the drumin one direction forces the batch toward the front end of the drum, androtation in the opposite direction forces the batch toward the rear endof the drum, thereby aiding in obtaining a thorough mixing. A water pipeIll extends axially of the drum and is provided with spray nozzles IIwhich spray water to the batch as the drum is rotated. The water iscarried in tanks which are not shown but which may be connected in anydesired manner to the pipe l0 so that water can be delivered to thebatch in the drum 2.

The drum is supported by rollers l2 and 13 which are mounted in theopposite ends of yokes II which extend transversely of and are supportedon the truck chassis. The yokes II have flat bases l5 which rest onrubber pads l5 which 5 in turn are supported by a framework l1 securedto the truck chassis. Longitudinal movement of the yokes I4 isrestrained by angle bars l8 as shown in Figure 1, and the yokes arerestrained from movement transversely of the chassis by bolts l9extending through the yokes l4 and angle bars.l 8.

The driving rollers l2 are secured to driving shafts and 26 which areconnected by means of a shaft 21 and flexible couplings 28. In thedisclosed embodiment only the rollers I! are driving rollers, therollers l3 simply acting as supports for the rotatable drum. The drivingshaft 25 is driven from an engine 30 through reduction and reversinggearing enclosed in a casing 3|. The reduction and reversing gearingwill be described more particularly hereinafter. The rotation of thedrum 2 may be reversed by operating a handle 32 located at the rear endof the drum. As the manual control for reversing the rotation of thedrum is used only while the batch is being discharged, the operator willbe standing at. the rear end of the mixer so that it is convenient tohave the operating handle 32 located at that point. The operating handle30 32 is connected to a rod 33 which extends lengthwise oi' the mixerand is slidably supported in brackets 34 secured to the yokes ll. Thefront end of the rod 33 is pivotally connected at 35 to a lever 36 whichis rigidly secured at its opposite end to a pin 31 which extends intothe gear casing 3|. The arrangement is such that upon rotation of thepin 31 a clutch shift lever hereinafter described, is shifted so as toreverse the rotation of the drum. A link 38 is rigidly secured at oneend to the pin 31 and at its other end is pivotally connected to a rod39 which connects with the governor 40 of the engine. 'A brake ll isconnected through a lever 42 and a link 43 to the lever 36, theconnection being 45 such that when the clutch shift lever 01' thereversing mechanism is in neutral position the brake is applied to theshaft 25.

It will thus be seen that by operating the handle 32 while the operatoris standing at the rear of the mixer, the drum may be rotated in eitherdirection, or if the clutch is thrown into neutral position, therotation of the drum may be stopped and the brake applied.

Instead of reversing the rotation of the drum just described, provisionis made for automatically and periodically reversing the rotation of thedrum during the mixing operation. As previously described, this forcesthe material alternately toward opposite ends of the drum so as toobtain a thorough mixing of the material. The automatic reversingmechanism is illustrated in Figures 4 to 7 inclusive. The left hand endof the driving shaft 45 is splined for connection with the engine driveshaft so that the shaft 45 always rotates in the same direction.Rotatably mounted on the shaft 45 are two beveled gears 46 which arespaced apart and which mesh with a ring gear 41 on opposite sidesthereof, the ring gear being secured to a shaft 48 mounted in bearings48 and 58. A spur gear 6| is secured to the shaft 48 and meshes with aspur gear 52 secured to the shaft 25 which drives the rollers I 2,thereby causing rotation of the mixing drum. The driving shaft 45 isprovided with clutches 55 and 56 as illustrated in Fig. 7 which may beshifted to the right or to the left in order to cause either one of thebeveled gears 46 to rotate with the shaft 45. Any usual clutch mechanismwhich will cause either one of the beveled gears 45 to rotate with theshaft 45 may be employed and since this clutch mechanism is not claimedby applicant to be novel per se, a detailed description is not givenherein. For causing either one of the beveled gears to rotate with thedriving shaft 45, a clutch shift lever 51 is employed. As shown in Fig,4 the lever 61 is keyed to the pin 81, one end 58 of the lever beingforked to receive a pin 58 secured to a collar 68 which fits into agrooved ring 6| shown in Figure '7. The rear end 55 is forked to receivea pin 65 secured to a yoke 61 which can be oscillated to the right andto the left as viewed in Figure 4, the yoke being guided in itsoscillation by arms 68 and 68 which slide in guides 18 and H, the arm 68being provided with a groove I2 which receives a pin I8 screwed into theguide I8. It will be seen that as the yoke 51 is oscillated to the rightor to the left from the position illustrated in Figure 4, it will shiftthe clutch 55 or 56 through the clutch shift lever 51 so as to causeeither one of the beveled gears 45 to rotate with the shaft 45, therebycausing the shaft 25 to rotate in one direction or the other, dependingupon which one of the beveled gears 46 is connected to rotate with theshaft 45.

In order to cause the yoke 61 to oscillate to the right and then to theleft as viewed in Figure 4, so as to reverse the rotationof the drum,the right hand end of the shaft 45 is provided with a worm I whichmeshes with a worm gear I6 secured to a horizontally extending shaft 11.The shaft 11 has a worm I8 secured thereto which meshes with a worm gearI8 secured to a vertical pin 88, the pin being mounted in bearings 8|and 82. Secured to the pin 88 below the worm gear 18 is a cam 83. As thecam is rotated it causes oscillation of a yoke-shaped cam follower 84alternately to the right and then to the left as viewed in Figure 4, thefollower being provided with rollers 85 which contact with the cam. Thefollower oscillates in guides II and 86. A pin 88 extends through anopening in the follower 84 and is received in an opening 8| in the guidearm 68 of the yoke 61. The upper end of the pin 88 is formed in an eye8| in which is received a pin 82 carried by a yoke 83 secured to thelower end of a plunger 84. A spring 85 surrounds the through manualcontrol of the handle 32 as plunger and in the position indicated inFigure 6 forces the plunger downwardly so as to cause the pin 88 toenter the opening 8|. The upper end of the plunger 84 is provided with awasher and nut which are received in a hollow nut 86. When the pin 88 isreceived in the opening 8| as shown in Figure 6, the rotation of thedrum is periodically and automatically reversed through the mechanismabove described. However, if the nut 86 is screwed upwardly, it raisesthe pin 88 from the opening 8| so that even though the driving shaft 45continues to rotate, it does not cause reversal of the drum rotation.When the pin 88 is raised from the opening 8|, the reversal of the drumis controlled manually by operating the handle 32. As above described,operation of the handle 82 causes a rotation of the pin 31, therebyshifting the clutch shift lever 51 and causing reversal of the drumrotation.

The arrangement of the reversing and reducing mechanism as illustratedin Figures 4 and 5 is such that a very great reduction is obtained in asmall space. The arrangement is particularly adapted for use inconnection with a truck mixer because the space available for suchmechanism is small. The ring gear 4'! is formed with two crowns I8I andI82 so that the clutches 55 and 56 may be received within one of thecrowns and the collar 68 and the end of the clutch shift lever 51 may bereceived within the other crown of the ring gear. The bearing 48 is sodesigned that the ring gear may be slid to a slight extent into thebearing in order to move the ring gear so that the clutch mechanism andshaft 45 may be removed as a unit from thecasing 8| without disturbingthe other parts. For this purpose the casing 3| is provided at thebottom as viewed in Figure 5 with an opening I83 of sufficient size sothat the clutch unit may be removed without disassembling it, theopening I83 normally being closed by a cover I 84.

Concrete or other material can be mixed more thoroughly by the methodherein described than if the mixing apparatus were rotated continuouslyin one direction. The reversal of the mixing apparatus forces thematerial first to one end of the drum and then to the other end duringthe mixing process, even when water is being supplied to the batch, sothat a very thorough mixing is obtained. When it is desired to changefrom automatic to manual control for reversing the mixing apparatus, itis only necessary to screw the nut 86 upwardly to disengage the pin 88from the opening 8|. When it is desired to change from manual control toautomatic control, the nut 86 is screwed down, thereby forcing the pin88 downwardly so that when the pin comes directly over the opening 8|,it will be forced by the spring 85 into the opening and from that timeon, the reversal of the drum will be automatic.

Although the drum illustrated in the preferred embodiment of myinvention, is octagonal in cross-section, it will be understood that thereversal of the drum during mixing may be utilized irrespective of theshape of the drum.

Instead of using friction rollers for rotating the drum, as illustratedin the preferred embodiment, gears meshing with corresponding gears onthe drum may be employed, or any other suitable means may besubstituted.

I have illustrated and described the present preferred embodiment of myinvention. It is to be understood, however, that the invention may beotherwise embodied or practiced within the scope of the followingclaims.

I claim:

1. A reversing mechanism, comprising a driving shaft, a driven shaft, aring gear secured to the driven shaft, two beveled gears rotatable onthe driving shaft, said beveled gears meshing with the ring gear atopposite sides thereof, clutches for causing either one of said beveledgears to rotate with the driving shaft, a pivoted clutch shift lever, acam, gearing connected to the driving shaft for rotating the cam, areciprocating follower, a reciprocating yoke connected to one end of theshift lever, and a spring-pressed pin connecting said yoke and follower.

2. A reversing mechanism, comprising a driving shaft, a driven shaft, aring gear secured to the driven shaft, two beveled gears rotatable onthe driving shaft, said beveled gears meshing with the ring gear atopposite sides thereof, clutches for causing either one of said beveledgears to rotate with the driving shaft, a pivoted clutch shift lever, acam, gearing connected to the driving shaft for rotating the cam, areciprocating follower, a reciprocating yoke connected to one end of theshift lever, a pin slidable in the follower, said yoke having an openingfor receiving the pin, and biasing means tending to force the pin intothe opening.

HAROLD E. McCRERY.

